Quitting smoking allows the multiplication of healthy bronchial cells

Researchers from the Wellcome Trust Sanger Institute and University College London, in the United Kingdom, report in an article published on January 29, 2020, in the journal Nature that inhaling tobacco smoke contributes to adding 1,000 to 10,000 new mutations (more than a quarter of which are potentially carcinogenic) per bronchial cell to spontaneous mutations. These mutations, which can be of different types, are directly responsible for the occurrence of bronchial/lung cancers, which are the leading cause of cancer death due to tobacco. The good news concerns smokers who have quit, because the number of mutations observed in their bronchial cells gradually returns to the same number as that observed in the bronchial cells of never-smokers, which ultimately results in a reduced risk of developing cancer. Thus, the epithelial lining of the bronchi gradually becomes "healthy" again. This repopulation is likely occurring from cells that have escaped the genetic damage linked to tobacco smoke observed in their neighbors, these "healthy" cells being four times more frequent in ex-smokers than in smokers. These results explain, at least in part, why quitting smoking is effective at any age in preventing the occurrence of bronchial cancer. However, these results do not predict the development of other respiratory diseases linked to tobacco, such as chronic obstructive pulmonary disease, namely emphysema and chronic bronchitis. ©Generation Without Tobacco

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